front of the
joint, with the brachial artery and biceps tendon to its lateral side.
The radial nerve divides into its superficial and deep (posterior
interosseous) branches at the level of the lateral condyle.

In _examining an injured elbow_, the thumb and middle finger are
placed respectively on the two epicondyles, while the index locates
the olecranon and traces its movements on flexion and extension of the
joint. The movements of the head of the radius are best detected by
pressing the thumb of one hand into the depression below the lateral
epicondyle, while movements of pronation and supination are carried
out by the other hand. The uninjured limb should always be examined
for purposes of comparison.

In injuries about the elbow much aid in diagnosis is usually obtained
by the use of the X-rays; but in young children it is sometimes
impossible, even with excellent pictures, to make an accurate
diagnosis by means of radiograms alone. In cases of suspected
fracture, a radiogram should be taken with the back of the limb
resting on the plate, the forearm being extended and supinated. If a
dislocation is suspected and a lateral view is desired, the arm should
be placed on its medial side. In obscure cases it is useful to take
radiograms of the healthy limb in the same position.

FRACTURES OF THE LOWER END OF THE HUMERUS

The following fractures occur at the lower end of the humerus: (1)
supra-condylar fracture; (2) inter-condylar fracture; (3) separation
of epiphyses; (4) fracture of either condyle alone; and (5) fracture
of either epicondyle alone.

All these injuries are common in children, and result from a direct
fall or blow upon the elbow, or from a fall on the outstretched hand,
especially when at the same time the joints are forcibly moved beyond
their physiological limits, more particularly in the direction of
pronation or abduction. While it is generally easy to diagnose the
existence of a fracture, it is often exceedingly difficult to
determine its exact nature. Although the ulnar and median nerves are
liable to be injured in almost any of these fractures, they suffer
much less frequently than might be expected.

Ankylosis, or, more frequently, locking of the joint, is a common
sequel to many of these injuries. This is explained by the difficulty
of effecting complete reduction, and by the wide separation of
periosteum which often occurs, favouring the production of an
excessive amount of new bone,